Research On Fiber Combining Of High Power Blue Semiconductor Laser

450 nm blue semiconductor laser,with its special wavelength advantage,plays an important role in the laser welding field of high reflection and high thermal conductivity materials represented by copper,and has considerable development potential.At present,the power of blue light single tube is small,and the incoherent blue light combining is the core technology to obtain high power blue light semiconductor laser.In this thesis,the nubm08 5W 450 nm blue light semiconductor single tube,which is newly launched by Nichia,is used as the basic light source,and two ways of optical fiber combining and spatial combining are studied.The main work is as follows.In this paper,based on the application of blue laser in welding field,and taking the latest nubm08 5W 450 nm blue light semiconductor single tube as the basic light source,this paper proposes two ways of fiber beam combination and spatial beam combination,which can develop high power blue light semiconductor laser and meet the needs of industrial application.(1)Aiming at 200 W output power,ZEMAX software is used to design the optical path of single blue light tube fiber coupling and blue light spatial beam combining fiber coupling respectively.The contents are single tube collimation design,beam encryption system design and coupling system design in turn.The efficiency of theoretical simulation can reach more than 99%,which provides a theoretical basis for subsequent experiments.(2)In the single tube collimation design and output test experiments.The slow axis of the single tube output beam is collimated twice by using single cylindrical mirror and Galileo telescope group respectively,and the advantages and disadvantages of the two methods are analyzed.The water-cooling structure and fixed mode of single tube are designed,and the stable output of single tube 5W is realized,which lays a foundation for subsequent space beam combination and optical fiber beam combination.(3)In the space beam combining experiment,a single row of 7 single tubes are coupled into the multimode fiber with core diameter of 400 um NA0.22,and a stable output of about 25 W is obtained.Based on this,the number of single tubes is increased to 8,and then three rows of single tubes are used as a group,a total of 24 single tubes are coupled into the multimode fiber with core diameter of 400 um NA0.22,and a stable output power of about 88 W is obtained,and the overall efficiency is about 75%.In the same way,four rows of 32 single tubes are superimposed,and the size of the combined beam spot is controlled by the Galileo telescope system to expand the power again.(4)In the experiment of 7 * 1 fiber combiner,a single row of 7 single tubes are coupled into the 7 * 1 fiber combiner.The input core diameter is 200 um NA0.22,and the output core diameter is 400 um NA0.22.The stable output module with power of about 24 W is obtained,and the comprehensive efficiency is about 68%.According to the theory of fiber bundling,seven combiner output fibers are bundled,which leads to the actual coupling efficiency lower than the theoretical value.The corresponding improvement measures are put forward for the two schemes to improve the overall efficiency.